As for determining which animals have been strangled and not drained of their blood, we must understand that the focus was on the quantity of blood remaining in the meat of the animal. It was not the fact that the animal was strangled that kept it from being eaten, but the fact that it was never drained of its blood.
The Eocene constitutes the middle part of the Paleogene period (65-23 million years ago), preceded by the Paleocene and succeeded by the Oligocene epoch (34-23 million years ago); all of these periods and epochs were part of the Cenozoic Era (65 million years ago to the present).
Unlike the other ancient eras, the Proterozoic Era contains good evidence of fossils which were mainly from archaeans and bacteria. This evidence is the proof that living organisms were in abundance in this era. The Era lasted from 2.5 billion years to 543 million years ago. Two major living organisms in existence of eukaryotic cells. At the mid of the Proterozoic Era there was an increase in the atmospheric oxygen.